The present invention generally relates to a system and method for diagnosing Alzheimer's disease. More specifically, the present invention relates to a system and method for diagnosing Alzheimer's disease using imaging of a live patient.
Fractional anisotropy (FA) is a scalar value between zero and one that describes the degree of anisotropy of a diffusion process. A value of zero means that diffusion is isotropic, i.e. it is unrestricted in all directions. A value of one means that diffusion occurs only along one axis and is fully restricted along all other directions.
FA is a measure that has been used in diffusion imaging where it is thought to reflect fibre density, axonal diameter, and myelination in white matter.
More specifically, FA derived from magnetic resonance diffusion tensor imaging has previously been used solely for characterizing the white matter of the brain. Further, the gray matter of the brain, which includes the hippocampus and cortex, contains dendrites and is structurally different from the white matter. Previously, dendritic quantity has been measured only by histological methods.